Nova: "Bone Diggers"

19 Jun 2007

I've flipped to a Nova, titled "Bone Diggers," about Australian paleontology. They're interviewing Australian paleontologist John Long, formerly of the Western Australian Musuem -- now at Museum Victoria -- and showing a skeleton of "an animal that has puzzled paleontologists for a hundred years."

They go out on the Nullarbor Plain, which has "thousands" of deep-shaft caves. They got some e-mail from some spelunkers showing a spectacular skeleton, and have come to excavate and survey what else is there. Apparently, there is a huge threat of fossil poaching from these caves.

I really like this Nova -- it doesn't have any of the trumped-up controversy of most paleontology docs, and the narration is fairly minimal. There is a lot of opportunity for Long to explain things in his own words. And all the time is spent following the paleontologists -- you get a view of how they set up their camp, how they practice with rockclimbing gear, and the efforts they take to minimize the chance that poachers will track them to the cave. And you see them preparing the fossils: a half-million year old complete skeleton of Thylacoleo, eight new species of fossil kangaroos, and many other skeletons.

It's an ideal kind of site for filming, because the paleontologists just had to walk through the cave and find things on the surface. So it's not characteristic of the high failure-rate and large-scale digging out backdirt of many paleontological sites. But the site gives the opportunity to see the scientists reflecting on what they are finding, and several instances where the paleontologists are turning over bones and suddenly recognize that the bones represent a new species. So that's pretty cool.

And you see them don protective suits to take bone samples for DNA and radiometric dating. They have the idea that the bones may be among the most recent found of the Australian megafauna, but they turn out to be several hundred thousand years old. Which is quite stunning, since the bones look like they were placed in the cave very recently. It's amazing to imagine such a pristine environment, without dust or significant moisture, for a half million years.

Then, a bit over halfway through, they return to the museum and you see comparative work, with not only Long but also Rod Wells describing the biology of Thylacoleo. After this follows several sequences of research on the fossil, including a CT scan, a computer reconstruction of the endocast, laser scanning and virtual reconstruction to assess locomotor characteristics, an anatomical artist drawing a fleshed-out reconstruction and then sculpting one; the sculpture being laser-scanned, and finally animated. And then you see the skeleton on exhibit in the museum.

They find out interesting things; like the large clawed front paws for bringing down animals; the specialized, kangaroo-like chevron bones in the tail that indicate the Thylacoleo could take on an upright, tripod stance; and the flat-footed, bear-like walking style. I usually hate animated 3-d reconstructions of things, but in this case, the animal is so much a mixture of features from living models, that it seems really uncanny to have them put all together. So the model conveys a lot of information that can't be absorbed easily otherwise.

This is a really nice presentation of what paleontology is about -- from beginning to end showing people working on finding, preserving, and interpreting the fossils. Only in the last ten minutes does the show divert to other scientists musing on why the Australian megafauna disappeared; that's interesting and all, but I'm glad the show didn't focus on that problem. Because the Thylacoleo itself is interesting enough.

John Hawks is the Vilas-Borghesi Distinguished Achievement Professor of Anthropology at the University of Wisconsin—Madison. I work on the fossil and genetic record of human evolution (About me).

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